In papillary thyroid carcinoma (PTC), cancer progression is increasingly understood as a product of two intertwined signaling engines: MAPK and PI3K/AKT. While these pathways normally coordinate growth, differentiation, survival, and cell death, in PTC they can become persistently active through genetic alterations, enabling tumors to proliferate, evade apoptosis, and resist treatment.
MAPK signaling is described as a key early driver of tumorigenesis. Alterations such as BRAF and RAS changes, along with RET/PTC rearrangements and NTRK fusions, keep the RAF–MEK–ERK cascade firing. The most common event, BRAF V600E, appears in roughly 40–60% of cases and is linked to more aggressive behavior and reduced responsiveness to radioactive iodine therapy.
A central consequence of sustained MAPK activity is dedifferentiation. The review notes that continuous signaling can suppress thyroid-specific genes required for iodine uptake. As a result, tumors may lose the molecular traits that make radioactive iodine effective, pushing disease toward a more treatment-resistant state.
As PTC advances, PI3K/AKT signaling becomes more prominent. Aberrations in PIK3CA, PTEN, and AKT promote survival, angiogenesis, metabolic adaptation, invasion, and resistance to apoptosis. Although these changes are relatively uncommon in conventional early-stage PTC, they are reported more frequently in poorly differentiated and anaplastic thyroid cancers—stages associated with poorer outcomes.
Crucially, MAPK and PI3K/AKT do not operate in isolation. The pathways share receptors and signaling intermediates, and feedback loops allow one network to compensate when the other is blocked. Receptor tyrosine kinases—such as RET, EGFR, VEGFR, FGFR, PDGFR, and MET—can activate both axes, while RAS serves as an additional convergence point.
This extensive molecular crosstalk helps explain why targeted therapies sometimes fail: blocking one route can shift signaling through the other. The authors emphasize that combination strategies aimed at simultaneously dampening MAPK and PI3K/AKT signaling may help overcome adaptive resistance, although many approaches still require clinical validation.
Molecular diagnostics are positioned as the bridge between biology and personalized care. While fine-needle aspiration remains the first-line diagnostic method, a substantial fraction of nodules are indeterminate; targeted testing for BRAF V600E, RAS mutations, RET/PTC rearrangements, and NTRK fusions can refine malignancy risk, prognosis, and treatment selection.
Therapeutic targeting already reflects this precision framework. BRAF and MEK inhibitors suppress MAPK-driven disease, selective RET and TRK inhibitors address fusion-positive tumors, and multikinase inhibitors such as lenvatinib and cabozantinib are used in advanced radioactive iodine–refractory settings. Meanwhile, PI3K/AKT/mTOR-directed options remain under investigation.
Overall, the perspective frames PTC as a dual-axis tumor driven by pathway cooperation. By mapping how MAPK and PI3K/AKT communicate, clinicians may better select targeted treatments and improve outcomes for patients with aggressive, therapy-resistant disease.
Subject of Research: Not applicable
Article Title: The dual axis of tumorigenesis: MAPK and PI3K/AKT pathways in papillary thyroid carcinoma
News Publication Date: July 24, 2026
Web References: https://doi.org/10.18632/oncoscience.663 ; https://www.oncoscience.us/archive/v13/
References: DOI: 10.18632/oncoscience.663
Image Credits: Copyright: © 2026 Rathod and Parmar (CC BY 4.0)
Keywords: papillary thyroid carcinoma, MAPK pathway, PI3K/AKT pathway, RET/PTC, targeted therapy
